DARTMOUTH, Nova Scotia — A hurricane hurtling towards Nova Scotia is expected to topple trees and cause flooding when it makes landfall west of Halifax early Sunday night.

At 11 p.m. EDT, hurricane Juan had maximum sustained winds of 169 km/h, about 30 km/h faster than it was earlier in the day.

The fifth hurricane of the Atlantic season was centred about 845 kilometres south of Halifax, moving north-northeast at about 14 km/h.

The storm was picking up speed as it barreled towards the Maritimes and had jumped to the stronger classification of Category 2, said the Canadian Hurricane Centre in Dartmouth, N.S.

Category 2 hurricanes have winds of at least 154 km/h.

However, cooler waters were expected to slow its ferocity as it approached Nova Scotia's coastline, said meteorologist Ken Kirkwood.

He said he expects the storm to bring heavy rains and high winds to much of the Maritimes shortly after 6 p.m. ADT.

"It now, rather than hitting the eastern shore of Nova Scotia, looks like it will be fairly close to the Halifax area," Kirkwood said in an interview Saturday.

"It's not a strong hurricane. It will lose its hurricane status probably fairly quickly after it makes landfall."

But the storm's strong winds were still likely to topple trees and limbs heavy with foliage, he said. Storm surges of 1.5 metres may also cause soil erosion and flooding along the province's coastline from Lunenburg to the Canso Causeway.

Margaret Murphy, a spokesperson for Nova Scotia Power, said crews were on standby in case lightning strikes, high winds or falling branches cause power outages Sunday night.

Boaters in nearby waters were also being warned about gale- and storm-force weather.

A wind warning was in effect for all of Nova Scotia except for the westernmost area of the province, as well as all of Prince Edward Island, Iles de la Madeleine and the eastern half of New Brunswick.

Residents near Halifax and in central Nova Scotia, who will bear the brunt of the storm, will experience winds around 90 kilometres an hour, with gusts up to 140 km/h.

Winds will gust to 120 km/h in other areas affected by the warnings.

The Cape Breton highlands will see winds of up to 150 km/h as a local wind effect couples with the strength of hurricane Juan, Kirkwood said.

A heavy rainfall of up to 80 millimetres was forecast for all of mainland Nova Scotia and western Cape Breton.

Heavy rains of 50-80 millimetres were also expected for Prince Edward Island and western and southern New Brunswick.

The hurricane is expected to weaken and transform into an extratropical storm in the Gulf of St. Lawrence by early Monday.

Forecasters said the hurricane won't threaten the United States.

Juan is the 10th named storm of the Atlantic hurricane season, which began June 1 and runs through Nov. 30.

A new system, Tropical Storm Kate, formed Saturday far from land in the Atlantic, said forecasters at the National Hurricane Center in Miami.

Kate's centre was about 1,850 kilometres east-northeast of the Lesser Antilles in the northeastern Caribbean.

The last hurricane to hit Nova Scotia was Gustav on Sept. 12, 2002. It caused little damage, though it dumped more than 100 millimetres of rain and had wind speeds of over 120 km/h.

But Juan will more closely resemble Hortense, which toppled trees and downed power lines in September 1996 when it came ashore east of Halifax, said meteorologist Chris Fogarty.